6-Aminouracil derivatives

ABSTRACT

Novel 6-aminouracil derivatives of the formula   WHEREIN R1 is lower alkyl which may be substituted with hydroxy or lower alkoxy, R2 is halogen, nitro or lower alkyl and n is 0, 1 or 2, show a strong inhibitory action against adenosine -3&#39;&#39;, 5&#39;&#39; cyclic phosphate phosphodiesterase in vitro, and exhibit excellent pharmacological actions such as diuretic, platelet aggregation inhibitory and broncho-dilating actions.   D R A W I N G

United States Patent I19] Furukawa et al.

[ Dec. 2, I975 6-AMINOURACIL DERIVATIVES [75] Inventors: YoshiyasuFurukawa; Masahiro Suno; Sawami Nose, all of Osaka, Japan [73] Assignee:Takeda Chemical Industries, Ltd.,

Osaka, Japan [22] Filed; Sept. 10, 1973 [21] Appl, No: 395,448

OTHER PUBLICATIONS Stoll, "Chemical Abstracts, Volt 53 (I959) Col. 6273b.

Primary Examiner-Paul M. Coughlan, Jr. Assistant Examinerlames H,Turnipseed Attorney, Agent, or Firm-Wenderoth. Lind & Ponack [57]ABSTRACT Novel 6-amin0uracil derivatives of the formula wherein R islower alkyl which may be substituted with hydroxy or lower alkoxy, R ishalogen, nitro or lower alkyl and n is 0, I or 2, show a stronginhibitory action against adenosine -3', 5 cyclic phosphatephosphodiesterase in vitro, and exhibit excellent pharmacologicalactions such as diuretic, platelet aggregation inhibitory and bronchodilating actions.

I3 Claims, N0 Drawings 6-AMINOURACIL DERIVATIVES The present inventionrelates to novel and useful 6- aminouracil derivatives.

The present inventors have succeeded in producing novel o-aminouracilderivatives of the formula wherein R is lower alkyl which may besubstituted with hydroxy or lower alkoxy, R is halogen, nitro or loweralkyl and n is 0, l or 2, and further studies on these compounds (I)have unexpectedly revealed that they show a strong inhibitory actionagainst adenosine -3',- 5-cyclic phosphate phosphodiesterase in vitroand exhibit excellent pharmacological actions such as diuretic, plateletaggregation inhibitory and bronchodilating actions.

Thus, the principal object of the present invention is to provide thenovel 6-aminouracil derivatives of the formula (I) which have theexcellent pharmacological actions and another object is to provide apharmaceutical composition comprising one or more of these compounds. Afurther object is to provide a method for the production of the noveland useful G-aminouracil derivatives (1).

Referring to the formula (I), the lower alkyl represented by R may bestraight or branched chain and saturated or unsaturated, and may beadvantageously those having up to 4 carbon atoms, which are exemplifiedby methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, isobutyl, t-butyland 2-methylallyl. These lower alkyls may be substituted with hydroxyand/or lower alkoxy. The lower alkoxy may be preferably those having upto 4 carbon atoms such as methoxy, ethoxy, n-propoxy, allyloxy,n-butoxy. As the examples of the substituted lower alkyls, there may beenumerated B-hydroxyethyl, y-hydroxypropyl, B-methoxyethyl,B-ethoxyethyl, [3- methoxypropyl and the like.

The halogen for R may be any of chlorine, bromine, iodine and fluorine.The lower alkyl for R may be straight or branched chain and saturated orunsaturated, and may be advantageously those having up to 4 carbonatoms, which are exemplified by methyl, ethyl, n-propyl, allyl, n-butyl,sec-butyl and 2methylallyl.

In the formula (I), K may occupy any position of 0-, mand p-positions ofthe benzyl group when n is l, and two substituents of R which are sameor different, may occupy any two positions of o-, mand p-positions ofthe benzyl group when n is 2.

2 The 6-aminouracil derivatives (I) may be produced by, for example,reacting a 6-aminouracil compound of the formula 0 HIH lL (II) 0 NHwherein R is as precedingly defined, with a compound of the formula(III) wherein R and n are as precedingly defined and X is halogen, inthe presence of an inorganic base.

Referring to the formula (III), the halogen represented by X may be anyof chlorine, bromine, iodine and fluorine.

The 6-aminouracil compounds of the formula (II) are known compounds, andmay be easily prepared by a per se established method, e.g. described in.lournal of Organic Chemistry" l7, p. I879 et seq. (I95 I The compoundsof the formula (III) are also known and can be prepared by a per seestablished method, e.g. described in Journal of Organic Chemistry" l0,p. 228 et seq. (1945).

These compounds (Ill) may generally be employed in an amount of fromabout 2 to about l0 mols relative to one mol of the fi-aminouracilcompounds (II).

As the inorganic base, alkali hydroxide (e.g. sodium hydroxide,potassium hydroxide, lithium hydroxide, etc.) and alkali carbonate (e.g.potassium carbonate,

sodium hydrogen carbonate, etc.) may be mentioned as preferred examples,and it is advantageously used as an aqueous solution. Use can also bemade, with advantage, of an alkali metal alkoxide which is obtainable byreacting a monovalent alkali metal (e.g. sodium or potassium) with analcohol (e.g. methanol or ethanol). In this instance, an excess ofalcohol may be employed, in which case the alcohol will function as asolvent as well. Generally, such an inorganic base is preferably used inexcess, particularly about 2 to l0 molecular equivalents based on theb-aminouracil compound (II).

This reaction generally proceeds fast in a solvent. As the solvent,there may be advantageously employed aqueous alcohol (e.g. aqueousmethanol, aqueous ethanol, etc.) and dimethylformamide. Generally thereaction is preferably conducted at a temperature of from about to 120Cand, for better results, from about to C.

The reaction gives rise to the -aminouracil derivative (I) which has, inthe 3- and S-positions of the 6- aminouracil compound (II), a couple ofsubstituted or unsubstituted benzyl groups originating from the compound(Ill) used.

Thus-produced 6-aminouracil derivatives (I) can be easily recovered fromthe reaction mixture and purified by per se known means such asextraction, recrystallization, chromatography and the like.

The novel 6-aminouracil derivatives (I) show a strong inhibitory actionagainst adenosine-3',5'-cyclic reutical compositions containing one or(i he present compou. can be prepared by per s ontciitional methods forthe preparation of pow 'stlldS. tablets. pills. injections and the like.The

w o1" carriers may be determined depending upon '1 administration thesolubility of the com- .lc dosage of suc'r; e-aminouracil derivative .2upon the route purpose of administraother conditions. the advantageousdosage to 3 g. daily for human adults when it is to tistered tor thetreatment of. for example. irombosis. bronchial asthma and the like.lowing Examples are intended merely to illus- --ntiy prci' redembodiments of the present and not to restrict the scope ofthisinvention. Tipoughout the foregoing description as well as in ii:.cliovting Examples. Test and Claims. mg. ml., M, C and r.p.1n. rcs'iectivt-l r refer to milligram(sl. f s molarityi'ies).millimolarity(ies). degrees c and roundt's) per minute. in Examples. theA ansiiip between parts by weight and parts by volcorresponds to thatbetween grams and milliliters.

EXAMPLE 1 a solution of 1.55 part by weight of 1-ethyl-6- .rourucil in20 parts by volume of 95 (volumc/ llillCi ethanol there were added 6parts by volume of 1 (weight/volume) aqueous solution of sodium Jzoxidcand 2.4 parts by weight of benzyl chloride. mixture was refluxed understirring for 3 hours, i -r which time it was concentrated to drynessunder re JLCLl pressure and the residue was shaken well with y =ts avvolume tit chloroform and 50 parts by volter. The water furtherextracted t) parts by volume oi chloroform. The chloroform iayers werepooled and concentrated to dryness i. r reduced pressure. The residuewas dissolved in 1:; by volume of chloroform and the solution was run oncoiurnn packed with 50 parts by weight of silica The column was elutedwith 591) parts by volume of ofrn and the fractions containing thedesired 1 m were pooled and evaporated to dryness reduced pressure. Theorocedure yielded 1.04 L by weight ofl-ethyi-3.ii-tnsbcnzyi-darninouracil white powders. Ultravioletabsorption spectrum: I Ethan-n y Elementary analysis. Calculated for Cd-1 N 0 C. 71.62 9%; H, 6.31 7c; N. 12.53 in. Found C. 71.69 91'. H.6.43 7c; N, 12.35

EXAMPLE 2 To a solution of 3.4 parts by weight ofl-(B-hydroxycthyl)-6-aminouracil in 40 parts by volume of 95volume/volume) ethanol there were added 10 parts by volume of a 16%(weight/volume) aqueous solution of sodium hydroxide and 8.64 parts byweight of p-riitr0 benzyl bromide. The mixture was refluxed understirring for 15 minutes. after which time it was concen trated todryness under reduced pressure. The residue was shaken well with 50parts by volume of chloroform and 50 parts by volume of water. Theinsoluble residue was washed well with boiled water and recrystallizedtwice with each 300 parts by volume of acetone to obtain 1.2 part byweight of l-(B-hydroxyethylldfibis(p-nitrobenzyl)-6-aminouracil aspale-yellow needles melting at 225227C. Ultraviolet absorption spectrum:A 275 mp.

Elementary analysis Calculated for C H N O C. 54.40 /2. H. 4.33 /1 N.15.84 7c.

Found C. 5434 c; H, 4.30 N. 16.52.

EXAMPLE 3 [n 100 parts by volume of 95 (volume/volume) ethanol wasdissolved 549 parts by weight of 1-ethyl-6- aminouracil and. then. 15parts by volume of a 15 (weight/volume) aqueous solution of sodiumhydroxide and 6.48 parts by weight of p-nitrobenzyl bromide were added.The mixture was refluxed under stirring for 15 minutes, after which timeit was treated by a procedure similar to that described in Example 1.The procedure yielded 1.37 part by weight ofl-ethyl-3.5-bis(pnitrobenzyll-6-aminouracil as yellow granules meltingat 215217C.

Ultraviolet absorption spectrum:

Elementary analysis.

Calculated for C H N O C. 56.47 /c; H. 4.50 N. 16.46 70.

Found C. 56.62 7:; H. 4.71 70', N, 16.31

EXAMPLE 4 In parts by volume of 7o (volume/volume) ethanol was dissolved7 parts by weight of l-ethyl-- aminouracil and. then. 12 parts by volumeof a 15 (weight/volume) aqueous solution of sodium hydroxide and 3.64parts by weight of p-chlorobenzyl chloride were added. Under stirring.the mixture was refluxed for 1 hour. after which time it was treated bya procedure similar to that described in Example 1. The procedureyielded a syrup of l-ethyl-3.5-bis(p-chlorobenzyl)-6-aminouracil. Thesyrup was recrystallized from 5 parts by volume of ethyl ether to obtain1.1 part by weight of white granules melting at 157C.

Ultraviolet absorption spectrum: X 275 mp. 221 mu Elementary analysis.

Calculated for C l-l, N Cl-,O

C. 59.41 H, 4.74 N. 10.39 C1. 1754 7c.

Found C. 59.31 76', H. 4.79 7:; N. 10.37 "7r; Cl, 17.46

EXAMPLE 5 In 20 parts by volume of 95 (volume/volume) ethanol wasdissolved 1.55 part by weight of l-ethyl-6- aminouracil and, then, 4parts by volume of a 15 (weight/volume) aqueous solution of sodiumhydroxide and 281 parts by weight of p-methylbenzyl chloride were added.The mixture was refluxed under stirring for 1 hour and, then. treated bya procedure similar to that described in Example 1.

EXAMPLE 6 The reaction between the 6-arninouracil compounds of theformula (ii) and the compounds of the formula (III) in the presence ofan inorganic base is conducted in the same procedures as in thepreceding Examples to obtain the compounds listed in Table 1., all ofwhich are novel and useful and fall within the scope of the formula (I).

Table l TEST The inhibitory actions of representative 6- aminouracilderivatives (l) of the present invention against adenosine-3',5-cyclicphosphate phosphodiesterase were determined by the following procedure.

A mixture of 900 mlfof fresh bovine blood and 100 ml. of a 3.8(weight/volume) aqueous solution of sodium citrate was centrifuged at2,000 r.p.m. (rotor radius: 9 cm) for 10 minutes to separate asupernatant. The lower layer was again centrifuged at 3,000 r.p.m. for 8minutes to separate a further supernatant. The supernatants werecombined and centrifuged at 4,000 r.p.m. for 10 minutes to precipitateplatelets. Thus obtained bovine platelets were washed twice with eachSOml. of saline and suspended in ml. of a 0.025 M tris- HCI buffersolution of pH 7.5 and the suspension was Elementary analysis CompoundMolecular Calculated(%) Found r) Ultraviolet absorption formula spectrumand melting point l-isobutyl-3,5-bis(2,4- C 52.75 C 52.49 A max"'"" 283my. dichlorobenzyll-fic,,H,.N,0,cl. H 4.22 H 4.40 aminouracil N 8.38 N8.2l

(3128.32 027.96 Melting point; l8ll83C l-(B-methoxyethyl)-3,5- C 69.10 C69.23 A max 285 mp. bisbenzyl-6 aminouracil C l-l Nfl H 6.34 H 6.12 N11.48 N 11.11 l-aIlyl-3.5-bis(p-methyl- C 73.65 C 73.62 A max""'"''' 280mu benzyl)-6-aminouracil C fl N o, H 6.72, H 6.54 I

n 11.11; N 10.95 l-methyl-3,5-bis(2,4- l C7315 C 73.04 A max' 282mgdimethylbenzylJ-fi-amino- .C,,H"N@O, H -.7.,22 H 7.ll 1 uracil N 11.12 N10.85 v A EXAMPLE 7 Some examples of practical recipes in which thecompounds of this invention are utilized for the treatment of edema,brochial asthma, thrombosis, and the like are as follows: 40

twice subjected to the series of rapid freezing in a dry A. (Tablet) ou) l42thyHshsbenzymqminoumcu 20 m8 ice acetone bath and thawing at 37 C.Thus treated (2) lactose 35 m suspension was used as the bovlrleplatelet adenos1ne (3) corn starch I50 mg. [4) microcrystamne cellulose30 mg- 45 3 ,5 cyclic phosphate phosphodlesterase preparation. (5)magnesium swarm 5 mg ().l ml. of the above-mentioned preparation was ad-240 mg. mixed with 0.1 ml. of a 0.02 M aqueous solution of P lab!adenosine-3,5'-cyclic phosphate. 0.] ml. of a l, 2, 3, quantity of 4 andhalf quantity of 5 are thoroughly mixed, and then the mixture isgranulated. Remaining A: quantity of 4 and half of 5 are added to thegranules and compressed into tablets. Thus prepared tablets can furtherbe coated with a suitable coating agent, e.g. sugar.

l, 2, 3 and half quantity of 4 are thoroughly mixed, and then themixture is granulated. Remaining half of 4 is added to the granules andthe whole is filled into a gelatin capsule.

0.l-l0mM dimethylsulfoxide solution of a test com pound, 0.2 ml. ofa 0.5M tris-HCl buffer solution of pH 7.5, 0.1 ml. ofa 0.02 M aqueoussolution of MgSO 0.1 ml. of snake venom (concentration of l mg./ml.),and water in an amount to make the whole volume I ml. The mixture wasincubated at 37C for IS minutes, after which time 0.5 ml. of a lONaqueous solution of sufuric acid was added to the mixture. Then, theamount of the inorganic phosphate formed in the reaction mixture wasdetermined according to the method described in p. 8 et seq. of "Methodsin Biochemical Analysis Vol. 3 published by Interscience Publishers.Inc., New York & London, in 1956, and the inhibitory constant (Ki value)was calculated with regard to the respective test compounds. Theinhibitory constants of the respective compounds were compared with theinhibitory constant of theophylline, which is one of the most popularadenosine-3',S'-cyclic phosphate phosphodiesterase inhibitor, determinedunder the same conditions as above.

The results are summarized in Table 2 below.

Table 2 3. The -aminouracil according to claim 1, wherein n CompoundInhibitory action against bovine platelet adenosine- 3 .5 '-cyclicphosphate phosphodicstcrase 4. The fi-aminouracil according to claim 1,wherein 5 R is halogen and n is l or 2.

5. The o-aminouracil according to claim 4, wherein the halogen ischlorine.

l -ethyl-3 ,5-bisbenzylo-aminouracil I75 times as strong as the actionof theophylline l-ethyl-3.5-bis(p- I08 times as strong chlorobenzyli-6-as the action of aminouracil theophylline l-ethyl-3.5-bis( p- 400 timesas strong methylbenzyll-6- as the action of aminouracil theophylline 6.The 6-aminouracil according to claim I, wherein R is lower alkyl havingup to 4 carbon atoms and n is m l or 2.

7. The G-aminouracil according to claim 6, wherein the lower alkyl ismethyl.

8. The 6-aminouracil according to claim 1, wherein R is nitro and n isI.

What is claimed is: 1. A o-aminouracil of the formula wherein R is loweralkyl having up to 4 carbon atoms which may be substituted with hydroxyor lower all:- oxy. having up to 4 carbon atoms. R is halogen, nitro orlower alltyl having up to 4 carbon atoms and n is 0.

lor2.

2. The G-aminouracil according to claim 1, wherein R is ethyl.

9. The fi-aminouracil according to claim I, which isl-ethyl-3,5-bisbenzyl-6-aminouracil.

10. The 6-aminouracil according to claim I, which isl-ethyl-3.S-bis(p-chlorobenzyl )-6-aminouracil.

1. A 6-AMINOURACIL OF THE FORMULA
 2. The 6-aminouracil according toclaim 1, wherein R1 is ethyl.
 3. The 6-aminouracil according to claim 1,wherein n is
 0. 4. The 6-aminouracil according to claim 1, wherein R2 ishalogen and n is 1 or
 2. 5. The 6-aminouracil according to claim 4,wherein the halogen is chlorine.
 6. The 6-aminouracil according to claim1, wherein R2 is lower alkyl having up to 4 carbon atoms and n is 1 or2.
 7. The 6-aminouracil according to claim 6, wherein the lower alkyl ismethyl.
 8. The 6-aminouracil according to claim 1, wherein R2 is nitroand n is
 1. 9. The 6-aminouracil according to claim 1, which is1-ethyl-3,5-bisbenzyl-6-aminouracil.
 10. The 6-aminouracil according toclaim 1, which is 1-ethyl-3, 5-bis(p-chlorobenzyl)-6-aminouracil. 11.The 6-aminouracil according to claim 1, which is 1-ethyl-3,5-bis(p-methylbenzyl)-6-aminouracil.
 12. The 6-aminouracil according toclaim 1, which is 1-( Beta-hydroxyethyl)-3,5-bis(p-nitrobenzyl)-6-aminouracil.
 13. The6-aminouracil according to claim 1, which is1-isobutyl-3,5-bis(2,4-dichlorobenzyl)-6-aminouracil.